PD20SL-4 / C-7401
20 sq ft replacement filter cartridge • 7″ OD × 6.5″ long
Ready to compare listings?
View PD20SL-4 replacement options on Amazon
Use the part-number links below to compare compatible cartridges. Prices and availability vary, so verify dimensions before ordering.
Cross-Reference & Interchangeable Part Numbers
| Brand | Part Number | Type |
|---|---|---|
| Pleatco | PD20SL-4 | Primary |
| Unicel | C-7401 | Equivalent |
| OEM | Doughboy 2396-020 | Original Equipment |
Always verify dimensions and end-cap type before purchasing a replacement.
Compatible Pool Filter Systems
| Brand | Model |
|---|---|
| Doughboy | 20 sq ft Pool Filter |
Frequently Asked Questions
What are the dimensions of the PD20SL-4?
The PD20SL-4 measures 7 inches in outer diameter and 6.5 inches in length, with a closed top and open bottom. It provides 20 square feet of filtration area. Always measure your existing cartridge or check the label inside the filter housing before ordering - outer diameter and length are the two critical dimensions, but end-cap style must also match.
What other part numbers are interchangeable with the PD20SL-4?
The PD20SL-4 is interchangeable with C-7401, and OEM equivalents including Doughboy 2396-020. All of these share the same 7" OD × 6.5" dimensions and closed top / open bottom end caps. When buying a cross-reference, confirm the end-cap style matches - a small difference in cap design can prevent proper seating in your filter housing.
How often should I replace a PD20SL-4 filter cartridge?
The PD20SL-4 (20 sq ft) is sized for smaller pool filter systems. Plan to inspect it every 3 months and replace it every 12-18 months. Heavy debris loads, high bather traffic, or imbalanced pool chemistry will shorten that timeline - if your filter pressure rises more than 8-10 psi above the clean starting pressure, it's time to clean or replace.
How do I clean a PD20SL-4 filter cartridge?
The PD20SL-4 has a closed (solid) top end cap. Remove the cartridge from its housing and rinse thoroughly with a garden hose, directing the stream at a 45-degree angle between the pleats - work from top to bottom, rotating around the cartridge. Avoid pressure washers, which collapse the pleats and permanently reduce filtration efficiency. For a deeper clean, soak the cartridge in a dedicated pool filter cleaner solution (following the product's dwell time instructions), then rinse completely before reinstalling. Having a spare cartridge on hand lets you swap and soak while the pool stays running.
Which hot tubs and spas use the PD20SL-4 filter?
Refer to your spa's owner manual or the label inside the filter compartment to confirm compatibility. The part number is usually printed on the end cap of the existing cartridge.
Dimensions
Specifications
| Outer Diameter | 7″ |
|---|---|
| Length | 6.5″ |
| Top Type | Closed (solid end cap) |
| Bottom Type | Open (no end cap) |
| Filtration Area | 20 sq ft |
| Primary Brand | Pleatco |
| Part Number | PD20SL-4 |